Add gitlab webhook support

templates/gitlab/messages/push.html

@@ -0,0 +1,27 @@
+{{ templates.repo_sender_prefix }}
+{% if is_deleted_ref %}
+    deleted branch
+{% else %}
+    pushed
+    <a href="{{ diff_url }}" data-mautrix-exclude-plaintext>
+        {{- total_commits_count }} commit{{ pluralize(total_commits_count) -}}
+    </a>
+    to
+{% endif %}
+ <a data-mautrix-exclude-plaintext href="{{ ref_url }}">{{ ref_name }}</a>
+{%- if is_new_ref %} (new branch){% endif -%}
+{%- if commits|length > 0 %}:
+    <ul>
+        {% for commit in commits[-5:] %}
+            <li>
+                <code><a data-mautrix-exclude-plaintext href="{{ commit.url }}">
+                    {{- commit.id[:8] -}}
+                </a></code>
+                {{ commit.cut_message|e }}
+                {% if commit.author.name != user_name and commit.author.name != user_username %}
+                    by {{ commit.author.name }}
+                {% endif %}
+            </li>
+        {% endfor %}
+    </ul>
+{% endif -%}